UNIVERSITY   OF   CALIFORNIA  Agricultural  Experiment  Station 

COLLEGE    OF    AGRICULTURE  E,    W.    HILGARD,     DIRECTOR 

BERKELEY,   CALIFORNIA 


CIRCULAR   No.  1 

(May,  1903.) 


TEXAS    FEVER 

By  ARCHIBALD   R.    WARD, 

Veterinarian  and  Bacteriologist. 


Synonyms.— Other  names  by  which  the  disease  is  known  are:  South- 
ern Cattle  Fever,  Bloody  Murrain,  Splenic  Fever,  Red  Water,  Tick 
Fever,  etc. 

Symptoms. — In  the  acute  (severe)  type  of  the  disease  a  fever  is  noticed, 
and  results  in  dullness,  lack  of  appetite,  and  constipation.  The  pulse 
and  respiration  both  increase  in  rapidity.  The  muzzle  and  mouth  may 
be  dry  and  the  head  usually  droops.  Affected  animals  prefer  to  stand 
in  water.  Some  animals  exhibit  extreme  dullness,  but  others  may  be 
delirious  and  unusually  active.  The  one  most  characteristic  symptom 
is  the  voiding  of  dark,  blood-colored  urine  by  animals  in  the  advanced 
stages  of  the  disease.  When  any  considerable  number  of  animals  are 
affected,  some  of  them  are  quite  sure  to  exhibit  this  symptom,  which  is 
of  great  value  in  recognizing  Texas  fever  to  those  unfamiliar  with  it. 
During  the  progress  of  the  disease  the  victims  grow  steadily  weaker, 
appearing  pale  and  bloodless.  The  attack  may  run  a  week,  and  result 
in  death  or  slow  recovery,  frequently  with  relapse.  Deaths  frequently 
occur  within  a  few  days  after  the  animal  is  noticed  to  be  ailing.  In 
some  animals,  not  very  susceptible  to  the  disease,  it  assumes  a  mild 
type,  manifested  by  dullness,  lack  of  appetite,  and  costiveness.  Texas 
fever  is  exclusively  a  cattle  disease  and  is  active  during  hot  weather. 

Post-mortem  Appearances. — The  liver  and  spleen  (milt)  are  the  organs 
most  usually  altered  in  appearance.  The  liver  is  enlarged,  and  the 
organ  is  not  as  tough  as  in  health.  The  color  is  usually  brownish  yel- 
low, due  to  bile  dammed  up  in  the  biliary  vessels.  The  gall  bladder  is 
distended  with  thick,  tarry  bile.  The  spleen  is  enlarged,  and  if  cut  open 
the  contents  will  flow  out  slowly  like  thin  jam.  The  blood  is  noticeably 
thin  and  pale.  There  occur  other  changes  not  readily  recognized  by 
persons  unfamiliar  with  the  study  of  diseases. 

% 


—  2  — 

Cause  of  the  Disease. — The  above-mentioned  changes  in  the  body,  and 
others  that  can  be  detected  only  with  the  microscope,  are  caused  by 
minute  animal  parasites  in  the  blood.  The  red-blood  corpuscles  are 
infested  with  the  parasites,  which  bring  about  the  destruction  of  the 
corpuscles  and  prevent  the  blood  from  performing  its  natural  function 
in  the  body.  The  blood-colored  urine,  in  severe  cases,  is  an  evidence  of 
the  breaking  down  of  these  corpuscles,  resulting  in  the  discharge,  through 
the  urine,  of  the  red  coloring  matter  of  the  blood,  which  is  normally 
carried  by  the  corpuscles.  The  microscopic  examination  of  the  blood  of 
an  affected  animal  will  reveal  the  parasites  imbedded  in  the  corpuscles, 
but  visible  only  as  small  round  or  pear-shaped  dots  even  with  the  best 
microscope.  The  parasites  are  always  present  in  the  blood  of  an 
animal  sick  with  Texas  fever,  but  under  certain  conditions  may  be 
present  in  limited  numbers  without  causing  sickness. 

How  Texas  Fever  is  Spread. — For  all  practical  purposes  we  may  con- 
sider the  disease  as  being  communicated  from  one  animal  to  another  by 
means  of  the  cattle  tick  (Boophilus  annulatus),  and  by  no  other  species 
of  tick.  The  disease  is  not  known  to  be  spread  by  any  other  means. 
The  habits  and  life  history  of  this  tick  are  intricately  involved  in  the 
spread  of  the  disease  and  furnish  explanation  for  all  of  the  principal 
peculiarities  observed  in  the  spread  of  Texas  fever. 

The  cattle  tick  lives  a  parasitic  life,  usually  in  some  unexposed  place, 
upon  the  hide  of  cattle,  sucking  the  blood.  If  the  blood  of  the  host 
contains  the  Texas-fever  parasites,  as  is  practically  always  the  case,  the 
ticks  become  infested  with  them.  When  the  female  ticks  reach  maturity 
(one  quarter  to  half  an  inch  long)  they  loosen  their  firm  hold  upon  the 
skin  and  drop  to  the  ground.  Each  female  may  lay  from  1,200  to  3,000 
eggs,  after  which  she  dies.  The  eggs  hatch  in  about  twenty  days,  but 
the  hatching  may  be  retarded  or  prevented  by  unfavorable  conditions, 
chief  among  which  is  brilliant  sunlight. 

The  young  ticks,  when  not  clustered  together,  are  readily  killed  by 
water;  and  a  temperature  of  15°  Fahr.  for  twenty-four  hours  will  kill 
them.  They  are  endowed  with  an  instinct  to  climb  upon  cattle  within  a 
few  days  after  hatching,  if  opportunity  occur;  but  in  the  absence  of 
cattle  (or  horses)  they  will  starve  in  time.  If  the  female  tick  has  been 
nourished  with  blood  containing  the  Texas-fever  parasites,  all  the  young 
ticks  hatching  from  her  eggs  will  contain  the  Texas-fever  parasites. 
When  such  a  young  tick  gains  access  to  an  animal  and  sucks  blood,  the 
Texas-fever  parasites  are  imparted  to  the  blood  of  the  animal  upon 
which  the  young  tick  is  living.  If  the  animal  infested  by  the  young 
ticks  is  susceptible  to  Texas  fever,  the  disease  will  appear  in  about  ten 
days  after  the  ticks  get  on  it.  The  ticks  mate  shortly  after  infesting  an 
animal,  and   nowhere  else;    after  which    they  become   firmly  fixed  to 


their  host  without  leaving  the  animal  until  ready  to  drop  off,  as  already- 
described. 

Since  cold  weather  kills  ticks,  their  eggs  and  young,  the  species  in 
question  is  limited  to  mild  climates.  During  the  summer,  ticks  may  be 
introduced  into  the  northern  parts  of  the  United  States  and  occasion 
immense  damage,  but  the  rigorous  winter  climate  exterminates  the 
ticks  and  consequently  the  disease. 

There  are  several  species  of  ticks  that  occasionally  are  found  on  the 
hides  of  cattle  or  in  their  ears;  but  only  one  kind,  popularly  known  as 
the  "fever  tick/'  is  concerned  with  the  spread  of  Texas  fever.  This 
species  practically  always  contains  the  Texas-fever  infection,  unless  it 
has  been  parasitic  upon  the  horse,  which  occurs  sometimes. 

The  Seventeenth  Annual  Report  of  the  Bureau  of  Animal  Industry 
at  Washington  contains  a  description  of  the  cattle  ticks  of  the  United 
States,  together  with  colored  illustrations.  The  book  can  in  most  cases 
be  obtained  from  Members  of  Congress,  or  by  purchase  from  the  Super- 
intendent of  Documents,  Union  Building,  Washington,  D.  C.  The 
Veterinarian  of  the  Agricultural  Experiment  Station  at  Berkeley  will 
be  glad  to  identify  specimens  of  ticks  sent  him  by  mail. 

Why  Ticks  May  Infest  Cattle  Without  Causing  Texas  Fever. — Among 
a  herd  of  cattle  infested  with  the  Texas-fever  ticks  the  calves  become 
infested  with  ticks  when  very  young,  and  suffer  a  mild  attack  of  Texas 
fever.  Calves  withstand  the  disease  readily  and  seldom  die.  As  a 
result  of  this  attack  they  grow  up  practically  immune  to  the  disease, 
and  are  usually  able  to  tolerate  the  presence  of  numerous  ticks  upon 
their  bodies.  This  immunity  is  not  absolute,  for  animals  excessively 
covered  with  ticks  may  again  contract  the  disease  under  especially 
unfavorable  conditions,  with  fatal  results.  The  fact  that  animals  may 
bear  ticks  without  necessarily  contracting  Texas  fever  has  induced  some 
people  to  refuse  to  believe  that  ticks  are  dangerous  under  any  conditions. 
Such  a  view  of  the  matter  is  indefensible. 

Conditions  Under  Which  Ticks  Are  Dangerous. — All  cattle  other  than 
young  calves  are  liable  to  contract  a  serious  type  of  Texas  fever  when 
first  bitten  by  infectious  ticks.  The  disease  is  therefore  a  menace  to  all 
cattle  raised  in  regions  where  cattle  ticks  do  not  exist.  Whenever  tick- 
infested  cattle  come  in  contact  with  non-immune,  i.  e.,  tick-free  cattle, 
some  of  the  latter  will  contract  the  disease  after  ten  days  or  more- 
Worse  yet,  the  disease  may  be  contracted  by  susceptible  animals  by 
feeding  upon  a  range  formerly  occupied  by  tick-infested  cattle,  for  young 
ticks  may  be  present  waiting  to  attach  themselves  to  the  cattle.  Losses 
will  occur  from  Texas  fever  when  tick-infested  southern  cattle  are  taken 
north  among  non-immunes,  just  as  soon  as  a  female  tick  drops  off  to 


__  4  — 

the  ground  and  the  second  generation  gets  upon  the  northern  cattle. 
Northern-bred  animals  will  contract  the  disease  when  taken  among 
ticks.  An  animal  may  be  bred  in  the  south  in  close  proximity  to  ticks 
and  yet  escape  them  until  it  reaches  adult  age,  when  it  will  suffer  from 
the  disease  if  infested  by  ticks. 

The  Federal  Quarantine  Line. — To  restrict  the  movement  of  cattle 
from  tick-infested  regions  to  tick-free  regions,  the  United  States  Depart- 
ment of  Agriculture  has  established  a  quarantine  line  across  the  con- 
tinent from  the  southern  boundary  of  Virginia  to  the  Bay  of  Monterey? 
in  California.  In  California  the  Federal  quarantine  line  lies  as  follows: 
"  Beginning  on  the  Pacific  Coast  where  the  northern  boundary  line  of 
"  Monterey  County  connects  with  the  Pacific  Ocean  ;  thence  easterly 
"  and  southerly  along  the  northern  and  eastern  boundary  line  of  Mon- 
"  terey  County  to  its  junction  with  the  western  boundary  line  of  Fresno 
"  County;  thence  northerly  along  the  western  boundary  line  of  Fresno 
"  County  to  the  western  corner  thereof ;  thence  northerly,  easterly,  and 
"  southerly  along  the  western,  northern,  and  eastern  boundary  line  of 
"  Merced  County  to  the  southeastern  corner  thereof ;  thence  north- 
"  easterly  along  the  northern  boundary  line  of  Madera  County  to  the 
u  northeast  corner  thereof ;  thence  southerly  and  easterly  along  the 
"  eastern  boundary  lines  of  Madera,  Fresno,  and  Tulare  counties  to  the 
"  southeast  corner  of  Tulare  County  ;  thence  easterly  along  the  southern 
u  boundary  line  of  Inyo  County  to  its  intersection  with  the  eastern 
"  boundary  line  of  the  State  of  California." 

The  line  marks  the  southern  boundary  of  the  region  free  from  ticks, 
and  is  moved  from  time  to  time  as  the  ticks  are  exterminated  from 
pieces  of  territory  contiguous  to  the  line  on  the  south,  or  as  the  ticks 
encroach  upon  the  territory  to  the  north  of  the  line.  Under  the  regu- 
lations of  the  United  States  Department  of  Agriculture  and  the  laws 
of  California  the  movement  of  cattle  across  the  line  is  restricted  so 
as  to  minimize  the  losses  from  Texas  fever.  Tick-infested  cattle  des- 
tined to  a  slaughter-house  may  be  taken  across  the  line  at  any  time,  but 
others  from  certain  districts  may  be  transported  across  the  line  only 
when  inspected  by  State  or  county  inspectors  and  pronounced  free  from 
ticks.  There  are  many  districts  south  of  the  quarantine  line  in  Cali- 
fornia that  are  free  from  ticks,  and  consequently  cattle  therein  should 
be  and  are  allowed  to  be  taken  north  after  inspection.  For  more  exact 
information  concerning  the  regulations  affecting  the  movement  of  cattle 
address  inquiry  to  the  State  Veterinarian,  Sacramento,  California. 

Inoculating  for  Texas  Fever. —  Moving  susceptible  animals  into  tick- 
infested  regions  is  always  attended  with  risk.  Calves  taken  in  during 
the  winter  have  the  best  chance  to  escape.  At  that  time  the  ticks  are 
not  numerous,  and  the  age  of  the  calves  and  the  climatic  conditions  of 


—  5  — 

winter  favor  their  recovery  when  infested  by  the  ticks.  But  there  are 
numerous  occasions  when  it  would  be  desirable  to  move  susceptible 
adult  animals  on  to  tick-infested  ranges,  and  in  consequence  an  opera- 
tion known  as  inoculation  or  vaccination  has  been  devised.  The  process 
consists  in  transferring  to  the  susceptible  animal  some  blood  from  a  tick- 
infested  animal,  and  thereby  producing  an  attack  of  the  disease  usually 
mild  and  not  fatal ;  that  is,  the  animal  is  artificially  immunized  against 
Texas  fever.  The  operation  is  sometimes  designated  vaccination.  It 
is  most  safely  performed  in  California  during  the  winter  months  and  at 
a  time  when  feed  is  good,  as  these  conditions  are  conducive  to  the  recovery 
of  the  animal  from  the  inoculation  attack  of  the  fever. 

The  existing  methods  of  inoculation  for  Texas  fever  have  hardly  been 
simplified  enough  to  justify  recommending  their  use  by  men  unskilled 
in  the  work.  Inoculation,  unless  performed  by  a  man  thoroughly 
familiar  with  the  disease,  is  liable  to  lead  to  disastrous  results.  The 
writer  believes  that  he  is  ministering  to  the  best  interests  of  stockmen 
in  advising  the  employment  of  a  competent  veterinary  surgeon  to  do 
the  work.  This  so-called  vaccination  is  not  a  remedy,  and  should  not 
be  practiced  upon  sick  animals. 

Recognition  of  Texas  Fever. — The  disease  is  not  difficult  to  recognize. 
Practically  always  the  history  of  the  outbreak  shows  that  there  has  been 
the  movement  of  one  or  more  animals  in  such  a  way  as  to  result  in  the 
infestation  of  non-immune  animals  by  ticks.  One  must  not  expect  to 
succeed  in  finding  the  ticks  upon  a  freshly-infested  animal,  for  they  are 
so  small  as  to  practically  elude  discovery.  The  fact  that  they  could  not 
find  ticks  on  the  affected  animals  has  led  many  stock  owners  to  errone- 
ously conclude  that  their  cattle  were  not  suffering  from  Texas  fever. 
Further  facts  to  assist  in  recognition  are  fever,  gradually  increasing 
weakness,  and  voiding  of  red-colored  urine.  Conclusions  may  be  further 
strengthened  by  examining  the  liver  and  spleen  after  death.  Hogs  are 
not  injured  by  eating  the  flesh  of  cattle  dead  of  Texas  fever. 

Treatment  of  Texas  Fever. —  Removal  of  the  animals  from  the  infested 
range  is  essential.  The  removal  of  the  ticks  is  desirable,  but  attended 
with  considerable  difficulty.  With  large  numbers  of  range  stock  this  is 
accomplished  with  more  or  less  completeness  by  dipping  the  animals  in 
a  large  vat  constructed  for  the  purpose  and  containing  some  substance 
harmful  to  the  ticks.  A  grade  of  oil  known  as  extra  dynamo  oil  has  been 
used,  floating  in  a  layer  several  inches  deep  on  the  vat  of  water.  One 
per  cent  of  sulfur  has  been  found  to  improve  its  action.  Fish  oil  has 
been  used  successfully  in  the  same  manner  in  a  vat  or  has  been  applied 
to  tame  cattle  by  hand,  with  satisfactory  results.  Cooper  Curtice  sug- 
gests the  following  mixture :  Kerosene  and  lard,  of  each,  one  gallon ; 
sulfur,  one  pound,  and  two  pounds  of  pine  tar.     Melt  the  lard,  to  which 


—  6  — 

should  be  added  the  tar  and  sulfur,  all  of  which  is  brought  to  the  boil- 
ing point.  Cool,  and  stir  in  the  kerosene.  This  is  to  be  rubbed  over 
the  animal  daily.  Such  treatment  is  only  applicable  to  small  numbers 
of  domesticated  animals. 

Cottonseed  oil  has  been  used  with  success  on  small  numbers  of  cattle- 
Practically  all  of  the  numerous  dips  that  have  been  devised  are  unsatis- 
factory in  some  respects.  Some  injure  the  health  of  the  animals, 
especially  the  eyes;  others  are  inefficient  in  not  killing  the  ticks  with 
one  dipping.  Oil  dips,  on  the  whole,  are  the  most  satisfactory  of  all 
the  various  dips  that  have  been  tested  for  killing  ticks.  But  the 
operation  of  dipping,  however  necessary,  sometimes  tends  to  aggravate 
the  disease. 

Medical  treatment  is  practicable  only  when  it  is  desired  to  save  some 
particularly  valuable  animal.  A  dose  of  a  pound  and  a  half  of  Epsom 
salts,  together  with  an  ounce  of  ginger,  should  be  given  in  a  drench. 
Dr.  J.  C.  Robert,  of  the  Mississippi  Agricultural  Experiment  Station, 
advises  the  following  treatment :  "Administer  bisulfate  of  quinine  in 
"from  60  to  120  grain  doses,  dissolved  in  one  half  pint  of  water.  Give 
"  the  quinine  every  two  to  four  hours  as  long  as  the  temperature  of  the 
"animal  remains  above  103°  Fahr ,  then  gradually  decrease  the  dose. 
"  Should  the  animal  grow  weak,  it  should  have  combined  with  the  quinine 
"  from  one  to  three  ounces  of  alcohol  or  twice  that  amount  of  whisky. 
"  When  improvement  commences  the  administration  of  an  iron  tonic 
"  will  be  found  of  value.  We  may  prepare  such  a  tonic  by  the  use  of 
"  powdered  sulfate  of  iron  2  parts,  powdered  nux  vomica  1  part,  powdered 
"gentian  root  1  part,  sulfate  of  soda  2  parts,  and  common  salt  4  parts  ; 
"  mix  these  ingredients  and  give  to  a  grown  animal  from  one  to  one  and 
"one  half  heaping  tablespoonfuls  in  feed  twice  daily.  Too  much  pains 
"  can  not  be  taken  with  nursing  a  case  of  Texas  fever.  The  high  fever 
"  incident  to  the  disease  rapidly  exhausts  the  animal's  strength,  and 
"unless  the  proper  nourishment  and  care  is  given  death  may  result 
"  before  we  look  for  it.  Give  tempting,  nutritious,  laxative  diet  and  pure 
"drinking  water.  If  the  animal  refuses  to  eat,  drench  every  four  hours 
"  with  one  quart  of  sweet  milk  in  which  has  been  beaten  four  or  six 
"  raw  eggs." 

The  Eradication  of  Texas  Fever. — Since  practically  the  tick  alone 
spreads  the  fever,  the  extermination  of  the  tick  from  a  district  frees  that 
place  from  Texas  fever.  Removal  of  cattle  from  the  infested  range  and 
persistent  dipping  will  clean  the  cattle  of  ticks.  Exclusion  of  cattle 
from  a  piece  of  infested  territory  for  two  winters  and  the  intervening 
summer  will  free  the  place  from  ticks,  which  starve  out  for  lack  of  a 
host.     These  measures  are  chiefly  relied  upon  along  the  quarantine  line 


to  exterminate  the  tick,  resulting  in  the  removal  of  the  line  to  a  point 
south  of  the  freshly-cleaned  territory.  The  great  difficulty  in  accom- 
plishing the  work  lies  in  the  difficulty  in  persuading  all  stock  owners  to 
see  the  desirability  and  necessity  of  eradicating  the  tick,  and  in  inducing 
them  to  work  together. 


